Communication receiver with tone operated audio amplifier circuitry

Claim 2

A communication receiver for receiving carrier signals modulated by at least one control tone and intelligence, said receiver comprising a processing circuit for receiving the modulated signals and detecting the control tone and the intelligence therein, a decoder circuit coupled to said processing circuit and responsive to the control tone for generating at the output thereof a control signal, electronic switching means coupled to the output of said decoder circuit and responsive to the control signal to provide an enabling signal, said electronic switching means including timing means to cause said enabling signal to extend for a predetermined time interval beyond the termination of the control tone, an audio amplifier circuit having a first input coupled to said processing circuit output and a second input coupled to said electronic switching means, said audio amplifier circuit being rendered operative by said enabling signal for said predetermined time interval to amplify the detected intelligence from said processing circuit, a speaker coupled to the output of said audio amplifier circuit to convert the amplified detected intelligence into sound waves, and a manual override switch coupling a source of override signal to said electronic switching means and to said audio aMplifier circuit, said manual override switch being movable to a first position for coupling said override signal to said electronic switching means and to said audio amplifier circuit respectively to disable said electronic switching means and to maintain said audio amplifier circuit operative irrespective of whether said control tone is received, said manual override switch being movable from said first position to a second position to decouple said override signal from said audio amplifier circuit and thereby render said audio amplifier circuit inoperative.

Claim 3

The communication receiver set forth in claim 1, wherein said electronic switching means is a monostable multivibrator.

Claim 4

The communication receiver set forth in claim 1, wherein said electronic switching means includes a first transistor of one polarity having an input electrode and an output electrode and a second transistor of an opposite polarity having an input electrode and an output electrode, said timing means coupling the output electrode of one transistor to the input electrode of the other transistor, and the output electrode of said other transistor being coupled to the input electrode of said one transistor, the output of said decoder circuit being coupled to the input electrode of said other transistor, the output electrode of said one transistor being coupled to said audio amplifier circuit.

Claim 5

The communication receiver set forth in claim 1, wherein said electronic switching means is a monostable multivibrator having first and second conditions, said monostable multivibrator normally being in said first condition and being switchable to said second condition by said enabling signal, said monostable multivibrator automatically reverting to said first condition upon termination of said predetermined time interval, said override signal being operative to cause said monostable multivibrator to revert to said first condition.

Claim 6

The communication receiver set forth in claim 1, wherein said manual override switch is spring-biased to the second position thereof.

Claim 7

The communication receiver set forth in claim 1, wherein said manual override switch includes a button which, when depressed, is placed in said first position and which, when released, springs outwardly to said second position thereof.

Claim 8

The communication receiver set forth in claim 1, and further comprising a first isolating diode coupling said switch to said audio amplifier circuit, and a second isolating diode coupling said electronic switching means to said audio amplifier circuit.

Claim 9

The communication receiver set forth in claim 1, wherein said mechanical override switch is coupled in series with the source of override signal, said mechanical override switch being closed in said first position thereof and open in said second position thereof.

Claim 10

A communication receiver for receiving carrier signals modulated by at least one control tone and intelligence, said receiver comprising a processing circuit for receiving the modulated signals and detecting the control tone and the intelligence therein, a decoder circuit coupled to said processing circuit and responsive to the control tone for generating at the output thereof a control signal, an electronic switching means coupled to the output of said decoder circuit and responsive to the control signal to provide an enabling signal, said electronic switching means including timing means and a manual switch having a first position coupling said timing means in circuit in said electronic switching means to cause said enabling signal to extend for a predetermined time interval, said manual switch being movable to a second position thereof to take said timing means out of circuit with said electronic switching means and cause said enabling signal to terminate with said control tone, an audio amplifier circuit having a first input coupled to said processing circuit and a second input coupled to said electronic switching means, said audio amplifier circuit being rendered operatIve by said enabling signal for said predetermined time interval to amplify the detected intelligence from said processing circuit, and a speaker coupled to the output of said audio amplifier circuit to convert the amplified detected intelligence into sound waves.

Claim 11

A communication receiver for receiving carrier signals modulated by at least one control tone and intelligence, said receiver comprising a processing circuit for receiving the modulated signals and detecting the control tone and the intelligence therein, a decoder circuit coupled to said processing circuit and responsive to the control tone for generating at the output thereof a control signal, an electronic switching means coupled to the output of said decoder circuit and responsive to the control signal to provide an enabling signal, said electronic switching means including timing means and a manual switch having a first position coupling said timing means in circuit in said electronic switching means to cause said enabling signal to extend for a predetermined time interval, said manual switch being movable to a second position thereof to take said timing means out of circuit with said electronic switching means and cause said enabling signal to terminate with said control tone, an audio amplifier circuit having a first input coupled to said processing circuit and a second input coupled to said electronic switching means, said audio amplifier circuit being rendered operatIve by said enabling signal for said predetermined time interval to amplify the detected intelligence from said processing circuit, and a speaker coupled to the output of said audio amplifier circuit to convert the amplified detected intelligence into sound waves.

Claim 12

The communication receiver set forth in claim 9, wherein said electronic switching means includes a first transistor of one polarity having an input electrode and an output electrode and a second transistor of an opposite polarity having an input electrode and an output electrode, said switch and said timing means being coupled in series between the output electrode of one transistor and the input electrode of the other transistor, and the input electrode of said one transistor being coupled to the output electrode of said other transistor, the output of said decoder circuit being coupled to the input electrode of said other transistor, the output electrode of said one transistor being coupled to said audio amplifier circuit.

Claim 13

The communication receiver set forth in claim 9, wherein said electronic switching means is a monostable multivibrator having first and second conditions, said monostable multivibrator normally being in said first condition and being switchable to said second condition by said enabling signal, said monostable multivibrator automatically reverting to said first condition upon termination of said predetermined time interval when said switch is closed, said monostable multivibrator automatically reverting to said first condition upon termination of the control tone when said switch is open.

Claim 14

A communication receiver for receiving carrier signals modulated by at least one control tone and intelligence, said receiver comprising a processing circuit for receiving the modulated signals and detecting the control tone and the intelligence therein, a decoder circuit coupled to said processing circuit and responsive to the control tone for generating at the output thereof a control signal, electronic switching means coupled to the output of said decoder circuit and responsive to the control signal to provide an enabling signal, said electronic switching means including timing means and a first switch having a first position coupling said timing means in circuit in said electronic switching means to cause said enabling signal to extend for a predetermined time interval, said first switch being movable to a second position thereof to take said timing means out of circuit with said electronic switching means and cause said enabling signal to terminate with said control tone, an audio amplifier circuit having a first input coupled to said processing circuit and a second input coupled to said electronic switching means, said audio amplifier circuit being rendered operative by said enabling signal for said predetermined time interval to amplify the detected intelligence from said processing circuit, a speaker coupled to the output of said audio amplifier circuit to convert the amplified detected intelligence into sound waves, and a second switch coupling a source of override signal to said electronic switching means and to said audio amplifier circuit, said second switch being movable to a first position for coupling said override signal to said electronic switching means and to said audio amplifier circuit respectively to disable said electronic switching means and to maintain said audio amplifier circuit operative irrespective of whether said control tone is received, said second switch being movable from said first position to a second position to decouple said override signal from said audio amplifier circuit and thereby render said audio amplifier circuit inoperative.

Claim 15

A communication receiver for receiving carrier signals modulated by at least one control tone and intelligence, said receiver comprising a processing circuit for receiving the modulated signals and detecting the control tone and the intelligence therein, a decoder circuit coupled to said processing circuit and responsive to the control tone for generating at the output thereof a control signal, electronic switching means coupled to the output of said decoder circuit and responsive to the control signal to provide an enabling signal, said electronic switching means including timing means and a first switch having a first position coupling said timing means in circuit in said electronic switching means to cause said enabling signal to extend for a predetermined time interval, said first switch being movable to a second position thereof to take said timing means out of circuit with said electronic switching means and cause said enabling signal to terminate with said control tone, an audio amplifier circuit having a first input coupled to said processing circuit and a second input coupled to said electronic switching means, said audio amplifier circuit being rendered operative by said enabling signal for said predetermined time interval to amplify the detected intelligence from said processing circuit, a speaker coupled to the output of said audio amplifier circuit to convert the amplified detected intelligence into sound waves, and a second switch coupling a source of override signal to said electronic switching means and to said audio amplifier circuit, said second switch being movable to a first position for coupling said override signal to said electronic switching means and to said audio amplifier circuit respectively to disable said electronic switching means and to maintain said audio amplifier circuit operative irrespective of whether said control tone is received, said second switch being movable from said first position to a second position to decouple said override signal from said audio amplifier circuit and thereby render said audio amplifier circuit inoperative.

Claim 16

A communication receiver for receiving carrier signals modulated by at least one control tone, said receiver comprising a processing circuit for receiving the modulated signals and detecting the control tone therein, a decoder circuit coupled to said processing circuit and responsive to the control tone for generatIng at the output thereof a control signal, electronic switching means coupled to the output of said decoder circuit and responsive to the control signal to provide an enabling signal, said electronic switching means including timing means to cause said enabling signal to extend for a predetermined time interval beyond the termination of the control tone, an annunciator circuit having a first input coupled to said processing circuit and a second input coupled to said electronic switching means, said annunciator circuit being rendered operative by said enabling signal for said predetermined time interval, and a mechanical override switch coupling a source of override signal to said electronic switching means and to said annunciator circuit, said mechanical override switch being movable to a first position for coupling said override signal to said electronic means and to said annunciator circuit respectively to disable said electronic switching means and to maintain said annunciator circuit operative irrespective of whether said control tone is received, said mechanical override switch being movable from said first position to a second position to decouple said override signal from said annunciator circuit and thereby render said annunciator circuit inoperative.

Claim 17

A communication receiver for receiving carrier signals modulated by at least one control tone, said receiver comprising a processing circuit for receiving the modulated signals and detecting the control tone therein, a decoder circuit coupled to said processing circuit and responsive to the control tone for generatIng at the output thereof a control signal, electronic switching means coupled to the output of said decoder circuit and responsive to the control signal to provide an enabling signal, said electronic switching means including timing means to cause said enabling signal to extend for a predetermined time interval beyond the termination of the control tone, an annunciator circuit having a first input coupled to said processing circuit and a second input coupled to said electronic switching means, said annunciator circuit being rendered operative by said enabling signal for said predetermined time interval, and a mechanical override switch coupling a source of override signal to said electronic switching means and to said annunciator circuit, said mechanical override switch being movable to a first position for coupling said override signal to said electronic means and to said annunciator circuit respectively to disable said electronic switching means and to maintain said annunciator circuit operative irrespective of whether said control tone is received, said mechanical override switch being movable from said first position to a second position to decouple said override signal from said annunciator circuit and thereby render said annunciator circuit inoperative.

Claim 18

The communication receiver set forth in claim 13, wherein said annunciator includes an audio amplifier and a speaker coupled thereto.